I am going to try to give you as much information as possible, so please be patient and read through it.
Mods on a 96 Cobra: C&L MAF Meter with Trueflow Inlet Pipe. JMS Tuned Chip. Dr. Gas X-pipe.
Problem: I’m having a bucking/misfiring happening between 1000 to 3000rpms. It feels as if the motor is cutting out all together then it starts surging as it accelerates. If started out as a small stumble, but now it’s a full blown misfire.
Symptoms: It will not do it while the car is in warm-up mode. But the car has a hard time idling during warm-up, but once it’s warm it idles fine. After the car is warm is when the bucking starts. It will do it under part throttle load and full throttle between 1k and 3k rpms. Once the IMRC’s open the car noses over like its going to die then takes off like a rocket. Now if I am cruising down the interstate at say 2500rpms the car acts normal with no bucking. But as soon as I give it a little gas it starts to buck. Supposedly (and I have verified this) you are supposed to be able to put your car in 4th gear at 10 mph, floor it, and the car will pull smoothly to redline. I tried this test and the car bucks hard between 1500rpm and 3000rpm then it takes off and charges hard to the redline.
I have had zero problems with it above 4k rpms. The car pulls steadily without any hesitation.
What I’ve Tried: I removed the chip and the problem has stayed the same. Pulled to plugs and they look ok. Replace plugs with a set a Autolite 764's just in case. The car has a set of MSD 8.5mm Plug Wires that are about 4 months old, tested resistance which is in specs. I cleaned the IMRC’s about two months ago and the plates/controllers where moving freely. I have done the "is it working" test on the IMRC's by touching the actuating arms with my fingers and reved the motor above 3500rpm to verify that they open then close with no interference. I’ve also check for vacuum leaks. Ran some fuel system cleaner but have not changed the fuel filter because its 6 months old.
What could be causing this?
Mods on a 96 Cobra: C&L MAF Meter with Trueflow Inlet Pipe. JMS Tuned Chip. Dr. Gas X-pipe.
Problem: I’m having a bucking/misfiring happening between 1000 to 3000rpms. It feels as if the motor is cutting out all together then it starts surging as it accelerates. If started out as a small stumble, but now it’s a full blown misfire.
Symptoms: It will not do it while the car is in warm-up mode. But the car has a hard time idling during warm-up, but once it’s warm it idles fine. After the car is warm is when the bucking starts. It will do it under part throttle load and full throttle between 1k and 3k rpms. Once the IMRC’s open the car noses over like its going to die then takes off like a rocket. Now if I am cruising down the interstate at say 2500rpms the car acts normal with no bucking. But as soon as I give it a little gas it starts to buck. Supposedly (and I have verified this) you are supposed to be able to put your car in 4th gear at 10 mph, floor it, and the car will pull smoothly to redline. I tried this test and the car bucks hard between 1500rpm and 3000rpm then it takes off and charges hard to the redline.
I have had zero problems with it above 4k rpms. The car pulls steadily without any hesitation.
What I’ve Tried: I removed the chip and the problem has stayed the same. Pulled to plugs and they look ok. Replace plugs with a set a Autolite 764's just in case. The car has a set of MSD 8.5mm Plug Wires that are about 4 months old, tested resistance which is in specs. I cleaned the IMRC’s about two months ago and the plates/controllers where moving freely. I have done the "is it working" test on the IMRC's by touching the actuating arms with my fingers and reved the motor above 3500rpm to verify that they open then close with no interference. I’ve also check for vacuum leaks. Ran some fuel system cleaner but have not changed the fuel filter because its 6 months old.
What could be causing this?